The invention relates to a lock assembly for a vehicle hood.
In general it is desirable to design vehicle bodies in such a manner as to minimize the risk of injury to a pedestrian struck by the vehicle. Legislative provisions relating to this norm are to be anticipated in the future.
For the protection of pedestrians struck by vehicles, the vehicle body must be flexible enough to allow the impact surface struck by the pedestrian to be deformed, thereby absorbing the impact energy. Normally, this requirement can be met only if rigid structural parts of the vehicle body in typical impact areas are arranged at a sufficient interval from the deformable exterior of the vehicle body.
German patent document DE 199 22 455 C1 discloses a flexible arrangement of the hinges of a vehicle hood. In addition, German patent document DE 197 21 565 A1 suggests the use of sensors to monitor the area in front of the moving vehicle in order to detect an impending collision with a pedestrian. In such a case an actuator shifts a front hood into a sprung, raised latch position so as to create greater leeway for movement of the front hood in the ensuing impact.
An active system of similar function by means of which the front hood is raised into an elevated, sprung position when there is a risk of collision is also disclosed in German patent document DE 100 34 523 A1.
According to Japanese patent document JP 2002-19641 A, a counter-latch part fixed to a vehicle hood engages in latch parts of a lock assembly on the chassis side. The lock assembly housing is arranged on a chassis-side structural part in such a way that under excessive stressing of the hood it performs a swivel movement so that the hood is lowered beyond the normal closed position.
An assembly of similar function is demonstrated in Japanese patent document JP 2002-37129 A. Although in this case the chassis-side lock housing is immovably arranged on a chassis-side structural part, when the hood is overloaded in the closing direction, the lock elements interacting with the hood-side counter-latch part are pushed into a special position in which the hood likewise assumes a distinctly lower position compared to its normal closed position.
One object of the present invention is to afford good protection for pedestrians in the area of the lock assemblies of a vehicle body hood, using an especially simple design construction.
This and other objects and advantages are achieved by the lock assembly according to the invention, which is based on the general principle of employing hood-side measures to limit the support forces produced on the lock assembly in the event of an impact acting on the closed hood in the closing direction to a predefined design limit. Thus, in the event of a corresponding overload on the hood, there is also a large amount of travel available in the area of the lock assembly for the absorption of impact energy. The additional flexibility in the area of the lock assembly can be readily designed with a pronounced directional characteristic, in such a way that in the opening direction of the closed hood exceptionally large forces can be absorbed without deformation of the lock assembly and/or adjoining structural parts, while additional flexibility under additional stressing in the closing direction is possible given the comparatively small forces that typically occur in vehicle collisions with pedestrians. The additional flexibility should typically take effect when forces of approximately 1,000 N act in the closing direction in the lock area.
Other objects, advantages and novel features of the present invention will become apparent from the following detailed description of the invention when considered in conjunction with the accompanying drawings.